Finned heat exchangers



June 29, 1965 w. c. JONES 3,191,670

FINNED mm EXC NGERS United States Patent 3,191,670 FTNNED TEATEXCHANGERS William 6. Tones, Medford, Mass, assignor to WestinghouseElectric Corporation, East iittsburgh, Pa., a corporation ofPennsylvania Filed 11113 24, 1961, Ser. No. 126,263 1 Claim. (Cl. 16576)This invention relates to heat exchangers having finned tubes in metalcasings.

Many heat exchangers used for the cooling and heating of air, consist ofspaced-apart, hollow tubes having closely spaced, plate-type fins commonto all tubes, supported in protective casings having air inlets andoutlets, and having headers at the ends of the tubes. In prior heatexchangers of this type, the casings have had sheet metal, top andbottom walls in contact with the tops and bottoms respectively, of thefins, and the finned tube cores have been held in the casings bystructural angles attached to the top and bottom walls, and contactingopposite edges of the fins.

This invention forms internally bulging ribs in the iongitudinal centersof the top and bottom walls of a casing, and forms complemental-shapednotches in the centers of the tops and bottoms of the fins, with theribs fitting snugly in the noches. Advantages of this construction arethat the ribs stifien the sheet metal top and bottom of a casing; theribs in the notches in the fins locate and hold the core in the casing,and the ribs in the notches prevent air from by-passing the core byflowing between the top and bottom walls and the core.

An object of this invention is to stiffen the sheet metal top and bottomwalls of a casing of a heat exchanger by forming ribs in thelongitudinal centers of the walls.

Another object of this invention is to use ribs in the longitudinalcenters of the top and bottom walls of the casing of a heat exchangerhaving plate-type fins, and notches in the centers of the tops andbottoms respectively, of the fins for locating and holding the finnedtube core within the casing.

Another object of this invention is to use ribs in the top and bottomwalls of a casing of a heat exchanger having plate-type fins, andnotches in the centers of the tops and bottoms respectively, of the finsfor preventing the bypassing of air around such ends.

This invention will now be described with reference to the annexeddrawings, of which:

FIG. 1 is a perspective view of a heat exchanger embodying thisinvention;

FIG. 2 is a section along the lines 22 of FIG. 1, and

FIG. 2 is a section similar to FIG. 2, but showing a Wider heatexchanger having difierently shaped ribs and notches.

Referring first to FIGS. 1 and 2, a row of vertically aligned, parallel,spaced-apart, hollow tubes 10, has ve1ti cally-extending,closely-spaced, plate-type fins 11 of sheet metal around and in contactwith all of the tubes 10. The tops and bottoms of the fins 11 havesemi-circular notches formed in the centers, and in which are fittedsemi-circular ribs 12 and 13 respectively, in the longitudinal centersof the sheet metal top wall 15, and bottom wall 16 respectively, ofcasing 17 The top wall 15 has end portions 18 which extend normalthereto, and has inturned portions 19 at the upper ends of the portions18, which extend parallel to the Wall 15. The bottom Wall 16 has endportions 20 which extend normal thereto, and has inturned portions 21 atthe lower ends of the portions 20, which extend parallel to the wall 16.The wall portions 18 and 20 have perforations 22 and'23 respectively,for receiving rivets or bolts for securing a duct to the casing 17.

3,191 ,670 Patented June 29, 1965 'ice A flanged end plate 25 hasoutwardly-turned portions 27 which extend across and are attached to theends of the wall portions 19 and 21, and has outwardly-turned portions23 which extend across and are attached to the ends of the wall portions18 and 20, at one end of the casing 17. A similar, flanged end plate 30has outwardlyturned portions 31 which extend across and are attached tothe ends of the wall portions 19 and 21, and has outwardly-turnedportions 32 which extend across and are attached to the ends of the wallportions 18 and 20 at the other end of the casing 17 A tie rod 40extends through the walls 15 and 16 midway between the end plates 25 and30 and to one side of the fins 11, and has threaded ends with nuts 41thereon above and below the walls 15 and 16. A similar tie rod 42extends through the walls 15 and 16 opposite the tie rod 40 on the otherside of the fins 11, and has threaded ends with nuts 43 thereon aboveand below the walls 15 and 16. The nuts 41 and 43 are adjustable on thetie rods 40 and 42 respectively, for moving the walls 15 and 16 towardseach other until the ribs 12 and 13 fit snugly into the notches providedtherefor in the tops and bottoms respectively, of the fins 11.

The end fins 11 are spaced from the end plates 25 and 30 for providingspaces for headers which are not shown. A typical tube connection 50 toone header is shown on FIG. 1.

FIG. 3 of the drawings shows another embodiment of this invention inwhich the heat exchanger core has three vertical rows of tubes 10A, andin which the fins 11A are wider than the fins 11 of FIG. 2 forcontacting the additional tubes. Also, the fins 11A of FIG. 3 havetriangular notches in their tops and bottoms in which are fittedtriangular ribs 12A and 13A respectively, in the longitudinal centers ofthe top and bottom walls 15A and 16A respectively. The remainder of thestructure of FIG. 3 is similar except as to size, as correspondingstructure of FIG. 2, and so has been given the same referencecharacters.

The ribs in the top and bottom plates by being drawn tightly into thenotches in the tops and bottoms of the fins, locates the finned core andholds it against displacement. By-passing of the air being conditionedaround the tops and bottoms of the fins is also prevented. The ribs alsostifien the sheet metal top and bottom plates.

What is claimed is:

A heat exchanger comprising a plurality of spacedapart, hollow tubeshaving parallel axes, a plurality of spaced-apart, parallel, plate-typefins around and in contact with said tubes, said fins having notches inthe centers of their ends, casing walls of sheet metal in contact withsaid ends of said fins and having ribs in their centers shapedcomplemental to the shape of said notches in said notches, and tie rodsextending through said walls on opposite sides of said fins, the ends ofsaid rods being threaded, and nuts on said threaded ends on oppositesides of said Walls.

References Cited by the Examiner UNITED STATES PATENTS 123,602 2/72Wiegard 130 1,208,790 12/16 Junkers 16585 2,267,905 12/41 Frantz 165-1222,599,965 6/52 Young 165-434- CHARLES SUKALO, Primary Examiner.

HERBERT L. MARTIN, ROBERT A. OLEARY,

Examiners.

